Hitch pins are commonly used to connect a drawn vehicle to the towing vehicle. For example, the farmer normally has a number of different implements which must be connected to the drawbar of a farm tractor. There are numerous designs of such pins for preventing the pin from inadvertently falling out from the drawbar. Obviously, if the pin inadvertently falls out and the towed trailer or implement becomes disconnected from the tractor, damage to the equipment or personal injury can result.
Pins have been designed which use a hasp that is inserted through an opening in the bottom of the pin after the connection is made. However, if the hasp is bumped or becomes caught on a cornstalk, for example, the hasp can be lost and the hitch pin can work its way out of the connection between the drawbar and the tongue of the drawn vehicle.
Some hitch pins are provided with a self-contained over-center wedge in the bottom end of the pin which wedge by force of gravity will pivot to a transverse position at the bottom of the pin thus preventing the pin from being withdrawn unless the wedge is manually moved into an upright position. However, through use, the wedge can bounce back into the pin or it can become bent and, therefore, fail to drop into a locking position.
Other hitch pins have used wire spring yokes or chain yokes some with catches or padlocks. The wire spring yokes can become easily broken, particularly when used to provide extra leverage for removing a tight pin.
There is, therefore, a need for a simple, durable self-locking hitch pin which will positively prevent the pin from inadvertently falling out of the connected members. It is further desirable that such a pin provide a means for increasing the leverage for removing the pin since in most instances the drawbar and tongue are applying forces on the pin which makes it difficult to remove. Such a pin should also be simple to manufacture and relatively low in cost.